Hi,

I hope you guys can help me with the following problem:

I have a quadrangle ABCD. <ADC = 135°, <ABC = 90°, [AB] = [BC]

That's all I know, but now I have to prove that [BD] = [AB] = [BC]

I tried some things with equations but it doesn't really work.

Thanks for your help!

Btw: I'm from Austria and I'm not a native speaker, so please feel free to correct my linguistic mistakes.